function Billboard(cellsWide, cellsTall){
	this.width = cellsWide;
	this.height = cellsTall;
	
	this.launchers = [];
	for(var i=0;i<cellsWide;i++){
		this.launchers[i] = [];
		for(var j=0;j<cellsTall;j++){
			this.launchers[i][j] = [];
		}
	}
}

Billboard.prototype.addString = function(dataString){
	for(var i=0;i < this.width * this.height;i++){
		var ch = dataString[i];
		var dbValue = letterDatabase[ch];
		if(dbValue == undefined)
			dbValue = letterDatabase["*"];
		var x = i % this.width;
		var y = Math.floor(i / this.width);
		this.launchers[x][this.height - y - 1].push(dbValue);
	}
};

Billboard.prototype.getParticles = function(){
	var particles = [];
	for(var i=0;i<this.width;i++){
		for(var j=0;j<this.height;j++){
			var placement = {
					pattern : this.launchers[i][j],
					y : j * 8 + 10,
					x : i * 6,
					startTime : 3.0,
					pace : 3.0,
					vSpacing : 1,
					launchers : 5
				};
				var physicsInfo = {
						gravity : 9.81
				};
				var launcherGroup = new LauncherGroup(placement, physicsInfo);
				for(var p=0;p < launcherGroup.projectiles.length;p++)
					particles.push(launcherGroup.projectiles[p]);
		}
	}
	return particles;
};